The Richard Gilder Graduate School embraces graduate training, post- doctoral fellowships, and undergraduate training programs at the Museum, through both independent activities and partnerships with universities.

Gerstner Scholar Profiles

2016-2018

Dr. Federico Lopez-Osorio

Research Focus – I study the evolutionary relationships and molecular basis of social behavior in wasps. Specifically, I focus on the subfamily Vespinae (yellowjackets and hornets). These wasps live in colonies usually including a single reproductive queen, and hundreds to thousands of sterile workers that raise the queen's offspring. Worker and queen castes in advanced societies of yellowjackets and hornets can be morphologically different and, unlike groups of primitively social wasps, individuals cannot switch between castes as adults. The field of sociogenomics aims to understand the origin of social behavior in molecular terms. The Vespinae are particularly interesting for comparative studies in sociogenomics because its close relatives in the family Vespidae exhibit a full range of social phenotypes, from solitary to primitively social. Moreover, the Vespinae include socially parasitic species, which have secondarily lost the worker caste and rely on parental care from workers of host species. Therefore, social parasites may allow the identification of changes in genetic architecture associated with the loss of free-living traits, such as maternal care and nest founding, or the gain of parasitic behavior.

For my research as a Gerstner Scholar, I will address three objectives. First, I will augment existing transcriptomic data, identify single-copy genes, and conduct a phylogenomic analysis of vespine wasps. Second, I will use the inferred phylogeny to search for evidence of positive selection, and I will test the ‘novel’ genes hypothesis, which states that sociality is the product of the evolution of genes lacking detectable sequence similarity to known genes. Lastly, I will characterize the transcriptomes of socially parasitic species and test for the predicted loss (or lack of expression) of genes associated with maternal care.

Biography - Federico Lopez-Osorio received his B.Sc. from the Universidad Industrial de Santander in Colombia in 2009, and completed his Ph.D. in 2016 at the University of Vermont, where Dr. Kurt M. Pickett and Dr. Ingi Agnarsson were his advisors. In his doctoral studies, he focused on molecular phylogenetics and comparative transcriptomics of yellowjackets and hornets.

Dr. Edward A. Myers

Research Focus – My postdoctoral research is focused on understanding variation in rattlesnake venom. Viperids, the family of snakes that includes rattlesnakes (Crotalus and Sistrurus), have venoms that are largely characterized as hemotoxic or hemorrhagic. However, a number of rattlesnake species and populations posses a potent neurotoxin. Despite these species being widespread within North America and being of medical importance, how these venoms have evolved is still unresolved. Recent studies have suggested that neurotoxic venoms are shared between rattlesnake species or populations because of past hybridization events (e.g. Zancolli et al. 2016 and Rokyta et al. 2015). However, other studies have concluded that the ancestor to all rattlesnakes possessed the genes responsible for these neurotoxins, and therefore species that lack this component in their venom have lost these genes at some point during their evolutionary history. My work will focus on addressing these competing hypotheses. In order to do so I will be generating RNA-seq data from venom glands and designing a set of DNA-probes to sequence venom genes across Crotalus. Ultimately this work will address how many times neurotoxin genes have evolved and whether hybridization plays a large role in the distribution of this trait across the rattlesnake phylogeny, which may contribute to our understanding of venom evolution in other snake groups as well as trait evolution in general.

In addition to the rattlesnake work, I will continue to work on population genomics and species delimitation in a number of North American snake taxa. This work seeks to address the mechanisms of speciation, while quantifying biodiversity within the US and Mexico. For example, collaborators and I are generating a genomic data set for the genus Pantherophis (rat snakes and corn snakes) to test species boundaries and to understand color pattern evolution in snakes.

Biography - Edward A. Myers received his B.Sc. in Zoology from Washington State University in 2009 and Ph.D. from the City University of New York in Biology in 2016, under the supervision of Dr. Frank Burbrink. His dissertation focused on comparative population genomics and ecological speciation of codistributed snakes across the desert southwest of North America.

Dr. Lu Yao

Research Focus – My research interests thus far have utilized phylogeographic analysis and phylogenetic comparative methods to answer a number of questions concerning the evolution of mammals on islands. For my postdoctoral work, I will be expanding on this research by studying gibbon evolution through a combination of genetics and morphology to better understand the intraspecific variation and level of hybridization within this highly endangered family of primates in Southeast Asia.

Gibbons (Hylobatidae) are relatively more speciose compared to other apes. Although some species are relatively well known, so far no attempts have been made to sample widely within each gibbon species to understand intraspecific variation and hybridization. My research is designed to use a combination of next generation sequencing techniques with morphometric analyses of wild gibbon specimens housed in museum collections around the world, including the extensive collections at AMNH, to expand knowledge about gibbon phylogeography, molecular evolution, and morphology at the population level. I will generate mitogenome, exome and single nucleotide polymorphism (SNP) data for a large selection of gibbon individuals across as many species as possible. With these data, I will be able to reconstruct a well-resolved intraspecific phylogeny, recognize hybridization events that may have occurred, and identify specific genes that experienced positive selection in different lineages. In addition to the genetic data, I am also collecting 3D morphological data from extant museum specimens along with alleged Hylobatidae fossils in order to analyze size and morphological variation between and within extant and fossil species. With this combination of genetic and morphological data, I intend to explore and illuminate the importance of intraspecific-level analyses, particularly in this group of understudied primates.

Biography - Lu Yao received her B.A. degree in 2011 from Northwestern University in the Integrated Science Program, Anthropology, and Biology. For her doctoral work, she was advised by Robert D. Martin and Corrie S. Moreau and studied the evolution of mammals on islands with a focus on long-tailed macaques. She received her Ph.D in 2016 from the Committee on Evolutionary Biology at University of Chicago.

2015-2017

Dr. James Herrera

Research Focus – For my postdoctoral fellowship, I am expanding my prior studies of diversification to investigate the mode and tempo of primate evolution. I am investigating how diversification has varied with biogeography, time, paleoenvironments and community composition for all primates across the globe and in deep time.

The first step is to infer a combined phylogeny for all primates, including both extinct and living taxa. I am gathering published and new morphological data for living and fossil primates from museum collections, including the extraordinary collections at the AMNH. I will combine these with molecular data available for almost all living species and several subfossil species. I then will apply a total evidence dating approach that determines the inferred speciation and extinction rates of the tree based on the fossils included in the analyses.

The second step is to compare speciation and extinction dynamics inferred from the phylogeny of only living species to those inferred from fossils. Estimates of speciation and extinction have been made from phylogenies of only living species, but the validity of these methods is contentious. I will compare the diversification dynamics estimated from different methods and test the most likely processes explaining diversification dynamics in deep time over the 65 million year history of Primates. I will quantify how species diversity varies across the evolutionary tree and test if age, diversification rate, biogeography and intrinsic traits explain the variation in observed species diversity.

My research also investigates the biogeography and community ecology in Madagascar by expanding from my previous studies of lemurs to include more taxonomic groups, including bats, carnivores, tenrecs, birds, amphibians, reptiles, fishes, and plants. I am seeking collaborations with specialists in these other groups to test if the patterns observed for lemurs hold for other groups as well. Finally, I am collaborating with other researchers to quantify the habitat loss around the measured communities to assess their threat status.

Biography - James Herrera received his Bachelors in Arts degree in 2009 from the University of Miami (FL) in Anthropology. He then earned his Master of Arts degree in 2011 from Stony Brook University (NY) in Anthropology and received his Ph.D. in 2015 from the Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University (NY).

Dr. Brendan Reid

Research Focus – My research interests lie in understanding and conserving turtle diversity. Turtles represent both an enormously charismatic and highly threatened group of reptiles, with approximately two-thirds of all turtle species considered to be at risk of extinction. They are morphologically and biogeographically extremely distinctive. While many other taxonomic groups are at their most diverse in the tropics, turtles instead exhibit their highest levels of species diversity in subtropical areas. In fact, the United States is home to more turtle species than any other nation, and the southeastern US is considered to be a global hotspot of turtle diversity. A better understanding of the processes responsible for creating and maintaining turtle diversity will help us understand how this diversity has survived in the face of shifting climates and habitats over the past several million years and how turtles may fare in the future.

Several roadblocks, however, still exist to understanding turtle diversity. Reproductive barriers among turtle taxa develop slowly, and ancient introgression as well as contemporary gene flow can obscure our understanding of past and ongoing speciation processes. Turtle DNA in general evolves relatively slowly compared to other vertebrate groups, and some recently-diverged turtle groups that exhibit a great deal of morphological diversity (such as the American map turtles) are still highly similar or identical for many traditional molecular markers used in evolutionary studies.

For my research at the AMNH, I will generate genomic single nucleotide polymorphism (SNP) data for an array of turtle species, focusing on pond turtles (family Emydidae) and mud turtles (family Kinosternidae) in North America. These data will be used to refine our understanding of recent evolution in these groups as well as to test hypotheses generated from paleophylogeographic species distribution models (which use present-day ranges, past climate reconstructions, and phylogenetic relationships to project species’ distributions into the past and to infer changes in distribution over time). By explicitly incorporating genetic data into range modeling, I intend to improve our understanding of how species’ ranges change over time, discriminate the effects of different potential drivers of species distributions (including climatic tolerances, local adaptation, and competitive interactions), and develop more accurate methods for predicting future changes in species ranges and the distribution of biodiversity.

Biography - Brendan Reid received his Masters degree in Conservation Biology from Columbia University in 2009. His Masters thesis project on genetic barcoding of turtles developed from a research internship at the AMNH, where he worked extensively with Museum research associates Dr. Eugenia Naro-Maciel and Dr. Minh Le. He has continued to work on various research topics (ranging from the genetic structure of spiny lobsters and New Guinea snapping turtles to the historical demography of green sea turtles) with AMNH scientists and other collaborators in the years since. For his Ph.D., Brendan studied under Dr. Zach Peery at the University of Wisconsin-Madison, where he investigated the ecology and conservation status of three wetland turtle species (including the endangered Blanding’s turtle) in the Midwest using demographic and landscape genetic approaches, obtaining his doctorate in 2015.

Dr. Nelson Salinas

Research Focus – I am trained as a botanist and have worked on Neotropical plant diversity over the last 15 years. Most of my previous research has been devoted to either floristics of the NW Amazon flora, or systematics of Neotropical plant groups, including blueberries (family Ericaceae), bromeliads (Bromeliaceae), and spiral gingers (Costaceae). More recently, I have become interested in biogeography, particularly in the estimation of ancestral ranges of tropical taxa, such as Ericaceae, and improving the delimitation of their geographical areas of endemism.

As a Gerstner Scholar, I am continuing my research on biogeography from a bioinformatics perspective. My current project aims to assess the adequacy of statistical models to describe patterns of geographic distributions of a variety of organisms. Attaining such a widely-applicable class of models will allow biogeographers to advance new tools for analysis, helping to incorporate uncertainty of geographical distribution data into historical range reconstructions and to implement more elaborate hypothesis testing procedures. As a first approximation to these models, I am beginning by developing an algorithm to infer areas of endemism, that is, geographic regions to which two or more taxa are likely to be restricted. This new algorithm will be tested against both simulated and empirical data, and implemented as a Python program that will be available to other researchers.

The empirical part of my Gerstner Scholar project includes biogeographic analyses of Neotropical blueberries (Ericaceae: Vaccinieae). These plants are ecologically important elements of the montane flora across Latin America, where they are usually found in well-preserved rain forests. Most species are epiphytic shrubs, which have bright, colorful flowers that are often pollinated by hummingbirds. Their diversity (around 600 species) and multiplicity of distribution patterns (from narrow endemics to widespread taxa) make them an excellent group to examine the efficacy of different methods to uncover areas of endemism.

Biography - Nelson Salinas received his B.Sc. in 2004 from the Universidad Nacional de Colombia, and his Ph.D. in 2015 in Biology from the City University of New York, in collaboration with the New York Botanical Garden. His doctoral research was focused on the taxonomy, phylogenetics, and biogeography of Neotropical blueberries.